Mechanisms Involved in Cardiac Sensitization by Volatile Anesthetics: General Applicability to Halogenated Hydrocarbons?

Water, Soil, Noise, and Light Pollution: JACC Focus Seminar, Part 2

Various forms of pollution carry a substantial burden with respect to increasing the risk of causing and exacerbating noncommunicable diseases, especially cardiovascular disease. The first part of this 2-part series on pollution and cardiovascular disease provided an overview of the impact of global warming and air pollution. This second paper provides an overview of the impact of water, soil, noise, and light pollution on the cardiovascular system. This review discusses the biological mechanisms underlying these effects and potential environmental biometrics of exposure. What is clear from both these pollution papers is that significant efforts and redoubled urgency are needed to reduce the sources of pollution in our environment, to incorporate environmental risk factors into medical education, to provide resources for research, and, ultimately, to protect those who are particularly vulnerable and susceptible.

New-Onset Intermittent Deceleration-Dependent Left Bundle Branch Block Following Induction of General Anesthesia in a Healthy Patient: A Case Report

This case report aims to highlight an atypical presentation of deceleration-dependent aberrancy (DDA) following the induction of general anesthesia in a patient with no known cardiac history. It emphasizes the critical role of intraoperative monitoring and the potential effects of anesthetic agents on the cardiac conduction system. A 46-year-old Hispanic male with no significant past medical or surgical history presented for surgical repair of a comminuted radial fracture. Following anesthesia induction with propofol, midazolam, and fentanyl, he developed a transient left bundle branch block (LBBB) exhibiting deceleration-dependent characteristics. Despite stable hemodynamics, the LBBB pattern appeared at heart rates below 60 beats per minute and resolved with heart rates above 90 beats per minute. This was managed intraoperatively with glycopyrrolate. Postoperative evaluations, including a 12-lead ECG, echocardiogram, and nuclear stress test, indicated normal biventricular function with a small to moderate reversible perfusion defect. The patient did not report cardiac symptoms postoperatively and did not prefer to undergo a coronary angiogram. This report underscores the importance of recognizing rate-dependent LBBB as a potential intraoperative complication, even in patients without pre-existing cardiac conditions. The transient nature of DDA, influenced by anesthetic agents and managed through careful monitoring and pharmacological intervention, highlights the necessity for vigilance in perioperative settings. This case contributes to a growing body of evidence suggesting that anesthetic management may require tailored approaches for patients experiencing or at risk for conduction abnormalities. This case illustrates the complexities of cardiac conduction disturbances such as DDA in the context of general anesthesia, serving as a reminder of the importance of thorough monitoring and the judicious use of rate-modifying drugs. It fosters a deeper understanding of the interaction between anesthesia and cardiac electrophysiology. Further research is needed to explore the mechanisms and management strategies for anesthetic-related cardiac conduction abnormalities.

1,1-Difluoroethane Hydrocarbon Cardiomyopathy

1,1-Difluoroethane (DFE) cardiomyopathy results from the direct inhalation of toxic halogenated hydrocarbons. We present a case series of acute DFE cardiomyopathy illustrating the typical presentation of severe DFE cardiomyopathy along with a detailed description of its mechanism of injury. (Level of Difficulty: Advanced.).

Huffing and twist: Fatal Torsade de pointes associated with Tetrafluoroethane Inhalation and amphetamine use

Many volatile chemicals inhaled for a recreational high have a chemical structure similar to chloroform and may lead to Ikr blockade and subsequent torsades de pointes. This is one potential mechanism of action for huffing-associated sudden death.

The last two decades on preclinical and clinical research on inhalant effects

This paper reviews the scientific evidence generated in the last two decades on the effects and mechanisms of action of most commonly misused inhalants. In the first section, we define what inhalants are, how they are used, and their prevalence worldwide. The second section presents specific characteristics that define the main groups of inhalants: (a) organic solvents; (b) aerosols, gases, and volatile anesthetics; and (c) alkyl nitrites. We include a table with the molecular formula, structure, synonyms, uses, physicochemical properties and exposure limits of representative compounds within each group. The third and fourth sections review the direct acute and chronic effects of common inhalants on health and behavior with a summary of mechanisms of action, respectively. In the fifth section, we address inhalant intoxication signs and available treatment. The sixth section examines the health effects, intoxication, and treatment of nitrites. The seventh section reviews current intervention strategies. Finally, we propose a research agenda to promote the study of (a) solvents other than toluene; (b) inhalant mixtures; (c) effects in combination with other drugs of abuse; (d) age and (e) sex differences in inhalant effects; (f) the long-lasting behavioral effects of animals exposed in utero to inhalants; (g) abstinence signs and neurochemical changes after interrupting inhalant exposure; (h) brain networks involved in inhalant effects; and finally (i) strategies to promote recovery of inhalant users.

Assessment of Methylene Chloride-Related Fatalities in the United States, 1980-2018

Importance

Methylene chloride is a halogenated organic solvent widely used in paint strippers, cleaners, adhesives, and sealants. Despite label warnings and occupational standards, methylene chloride-related fatalities continue to occur in the United States.

Objective

To identify and analyze methylene chloride-related fatalities in the US.

Design, Setting, and Participants

For this case series, we conducted systematic searches of sources, including PubMed and government databases, for unintentional fatalities in the US that were associated with exposure to methylene chloride or products containing methylene chloride between 1980 and 2018. We reviewed all available information, including inspection reports, autopsy reports, and medical records; data analyses were conducted from August 2018 to August 2020. Cases were categorized as those occurring in the home (consumer deaths) or at work (occupational deaths).

Exposures

Methylene chloride or products containing methylene chloride.

Main Outcomes and Measures

To determine characteristics of the methylene chloride-related fatalities, we recorded demographic information; the setting; circumstances, including information on safety measures used, if available; and products used. Where medical records were available, we recorded toxicology results and autopsy findings. We also obtained data about nonfatal methylene chloride cases from the American Association of Poison Control Centers.

Results

From 1980 to 2018, 85 methylene chloride-related fatalities were identified in the US, including 74 (87%) in occupational settings; of those who died, 75 (94%) were men, and for the 70 cases with available information, the median (interquartile range) age of the decedents was 31 (24-46) years. Paint strippers were the most common products involved in methylene chloride-related fatalities (n = 60). The proportion of occupational fatalities related to paint stripping increased from 22 (55%) before 2000 to 30 (88%) after 2000. Similarly, occupational fatalities associated with bathtub or paint stripping in bathrooms increased from 2 (5%) before 2000 to 21 (62%) after 2000. From 1985 to 2017, the American Association of Poison Control Centers documented 37 201 nonfatal methylene chloride cases, with a decrease in the annual number of cases starting in the late 1990s.

Conclusions and Relevance

Results of this case series demonstrated that despite regulations to address the toxic effects of methylene chloride use for consumers and workers, there are continuing fatalities in the US, particularly in occupational settings. Prevention of fatalities associated with methylene chloride exposure should emphasize the use of safer substitutes, rather than hazard warnings or reliance on personal protective equipment.

Solvent-based paint and varnish removers: a focused toxicologic review of existing and alternative constituents

Paint and varnish removers constitute a major potential source of organic solvent exposure to contractors and home improvement enthusiasts. Unfortunately, the leading paint remover formulations have traditionally contained, as major ingredients, chemicals classified as probable human carcinogens (eg, methylene chloride) or reproductive toxicants (eg, N-methylpyrrolidone). In addition, because of its unique toxicology (ie, hepatic conversion to carbon monoxide compounding generic solvent narcosis and arrythmogenesis), high volatility, and rigorous requirements for personal protective equipment, methylene chloride exposures from paint removers have been linked to numerous deaths involving both occupational and consumer usage. The aim of this review is to summarize the known toxicology of solvent-based paint remover constituents (including those found in substitute formulations) in order to provide health risk information to regulators, chemical formulators, and end-users of this class of products, and to highlight any data gaps that may exist.

Electrocardiographic changes and exposure to solvents

Background

Occupational exposures can cause cardiovascular disorders. Some exposures may be harmful, and exposures to chemicals such as metal welding fumes, gases, and pesticides, and stress related to physical and occupational hazard, which results in cardiovascular disorders such as arrhythmia, could be prevented. The objective of this study was to determine the electrocardiographic changes in occupational exposure to organic solvents.

Methods

It was a historical cohort study and was carried out on workers of industries. The study was carried out with flexible interview, physical examination, checklist for obtaining clinical history, and electrophysiology test. Group 1 included the workers in the production line of solvent and paint, group 2 included administrative personnel, and group 3 included workers from other industries who did not have solvent exposure. A number of participants in group 1, group 2, and group 3 were 500, 498, and 501, respectively. Electrocardiographic changes were recorded in health issues.

Results

The frequency of arrhythmia, P wave, and QRS complex changes were highest in group 1. The risk of arrhythmia was 1.15 (1.08‐1.49), P wave change was 1.02 (1.01‐2.28) which was significant and considered as highest risk,, and QRS complex change was highest in group 1, whose relative risk was 1.53 (1.46‐1.61). ST segment and T wave changes (depression or elevation) were highest in group 1 and had no significant differences (P < .05).

Conclusion

Working in solvent industry is a risk of developing arrhythmia. Exposure to chemical especially solvent agents mostly affects the cardiovascular system and is effective on electrocardiography, which must be prevented.

Evaluating real-time effects of topical 1:1000 epinephrine in endoscopic sinus and skull-base surgery on hemodynamic parameters through intraoperative arterial line monitoring

BACKGROUND

Administration of topical 1:1000 epinephrine is commonly used in practice to achieve vasoconstriction during endoscopic sinus surgery and skull-base surgery; however, real-time effects on cardiovascular changes from systemic absorption have not been well studied.

METHODS

Twenty-six patients undergoing endoscopic transsphenoidal resection of a pituitary lesion at a single institution were included into the study. Following arterial line placement by anesthesiology, 6 cottonoid pledgets soaked in 1:1000 epinephrine were placed into the bilateral nasal passages. Hemodynamic parameters including heart rate, blood pressure, and mean arterial pressure were collected at baseline, 30 seconds, and increments in minutes up to 10 minutes. Additional potentially confounding factors such as use of antihypertensives, stress dose steroids, and positioning with head pins were all performed following termination of data collection.

RESULTS

The majority of patients (20/26, 77%) showed no significant change in any parameter following placement of epinephrine soaked cottonoids. Six patients, however, had transient increases in blood pressure following administration of topical epinephrine, with a few requiring vasodilatory interventions. Return to baseline cardiovascular values were noted after an average of 7 minutes. There was no correlative preoperative characteristic that predicted sensitivity to placement of epinephrine. There were no lasting or permanent effects.

CONCLUSION

Although intranasal topical 1:1000 epinephrine use showed no substantial hemodynamic changes in the majority of patients, in a subset of patients it can cause significant transient elevations in blood pressure to a degree necessitating intervention. Topical epinephrine should be used judiciously in endoscopic sinus surgery.

Beyond Ether and Chloroform-A Major Breakthrough With Halothane

BACKGROUND

The use of equipment powered by electricity in the operating room increased the risk of fires in the presence of flammable agents such as ether and cyclopropane. Chloroform was associated with cardiac arrhythmias and liver damage. The introduction of halothane in the late 1950s was heralded as a solution to many problems facing the specialty of anesthesia. We explore whether the manufacturer promptly reported halothane's adverse effects to regulatory agencies and practitioners.

SOURCES

We consulted documents submitted by Ayerst Laboratories to federal authorities through the Freedom of Information Act, promotional advertisements, package inserts, published articles, and textbooks.

RESULTS

Two major complications associated with the use of halothane, cardiac arrhythmias and the risk of hepatotoxicity, were disclosed by the manufacturer when the drug was first introduced to the US market. Reports appeared timely and complete; there was no apparent attempt to conceal or otherwise downplay these risks.

CONCLUSION

The process of drug discovery and approval for clinical use has always been a lengthy, complex, and extremely expensive undertaking, with only a small minority of compounds receiving approval. The risk of adverse effects or drug interaction directly impacts commercial viability. In the case of halothane, the manufacturer disclosed major adverse effects, and the drug enjoyed decades of popularity until it was replaced by agents with a better drug profile.

Serial neuropsychological assessment of an adolescent girl after suffering a sudden out-of-hospital-cardiac-arrest following recreational inhalant use

Sudden out-of-hospital-cardiac-arrest (OHCA) following recreational inhalant use is well documented in the literature. The present case study reports the long-term neuropsychological sequelae of a 14-year-old girl who suffered an OHCA secondary to recreational butane gas inhalation. The patient was assessed on day-13 as an inpatient, and again at 3- and 12-month outpatient follow-ups. Acutely the patient demonstrated significant impairment on tasks associated with verbal and non-verbal memory and executive functioning. Re-testing at 3-months post-acute state suggested improved executive and non-verbal functions while showing continued deficits in verbal memory. At 12-months she was cognitively performing at levels expected for her age. This case is reported for its rarity in successfully being able to track the patient's clinical course from hospital discharge to the successful reintegration back into school and community settings.

Differential inhibition of cardiac and neuronal Na(+) channels by the selective serotonin-norepinephrine reuptake inhibitors duloxetine and venlafaxine

Duloxetine and venlafaxine are selective serotonin-norepinephrine-reuptake-inhibitors used as antidepressants and co-analgesics. While venlafaxine rather than duloxetine induce cardiovascular side-effects, neither of the substances are regarded cardiotoxic. Inhibition of cardiac Na(+)-channels can be associated with cardiotoxicity, and duloxetine was demonstrated to block neuronal Na(+)-channels. The aim of this study was to investigate if the non-life threatening cardiotoxicities of duloxetine and venlafaxine correlate with a weak inhibition of cardiac Na(+)-channels. Effects of duloxetine, venlafaxine and amitriptyline were examined on endogenous Na(+)-channels in neuroblastoma ND7/23 cells and on the α-subunits Nav1.5, Nav1.7 and Nav1.8 with whole-cell patch clamp recordings. Tonic block of the cardiac Na(+)-channel Nav1.5 and rat-cardiomyocytes (CM) revealed a higher potency for duloxetine (Nav 1.5 IC50 14±1µM, CM IC50 27±3µM) as compared to venlafaxine (Nav 1.5 IC50 671±26µM, CM IC50 452±34µM). Duloxetine was as potent as the cardiotoxic antidepressant amitriptyline (IC50 13±1µM). While venlafaxine almost failed to induce use-dependent block on Nav1.5 and cardiomyocytes, low concentrations of duloxetine (1, 10µM) induced prominent use-dependent block similar to amitriptyline. Duloxetine, but not venlafaxine stabilized fast and slow inactivation and delayed recovery from inactivation. Duloxetine induced an unselective inhibition of neuronal Na(+)-channels (IC50 ND7/23 23±1µM, Nav1.7 19±2µM, Nav1.8 29±2). Duloxetine, but not venlafaxine inhibits cardiac Na(+)-channels with a potency similar to amitriptyline. These data indicate that an inhibition of Na(+)-channels does not predict a clinically relevant cardiotoxicity.

Intensive care management following defibrillation of an adolescent girl after recreational inhalant use: a case report and review of the literature

We report the successful out-of-hospital defibrillation and intensive care management of a 14-year-old girl who developed ventricular fibrillation following the inhalation of two 150-mL butane cigarette lighter refill canisters. Following ambulance transport to the nearest tertiary pediatric health care facility, her acute clinical course consisted of sinus tachycardia, fluctuating consciousness, and severe cerebral agitation and combativeness. Over a period of 2 weeks, her neurological function significantly improved to the point she was able to be discharged back into the community, however, not without a number of formally identified neurological deficits. Inhalant gasses, through as yet unclear mechanisms, can cause the myocardium cell membrane to become unusually sensitive to catecholamines which in turn can sometimes lead to fatal arrhythmias. This case is reported for its rarity in terms of the patient being able to be discharged back into the community and to create awareness of the sudden and potentially devastating consequences of butane inhalant use for critical care physicians and prehospital health-care personnel.

Exposure to anesthetic gases and congenital anomalies in offspring of female registered nurses

BACKGROUND

Studies of offspring of mothers exposed to anesthetic gases have shown associations with congenital anomalies reported by the mothers, but rarely in studies with objectively ascertained outcomes. We conducted a retrospective cohort study to examine associations between registry-ascertained congenital anomalies in offspring and anesthetic gas exposure of mothers employed as nurses.

METHODS

A cohort of registered nurses in British Columbia, Canada, was linked to records of births and congenital anomalies from 1990 to 2000. Exposures were assessed via a survey of anesthetic gas use in all hospitals in the province and records of nurses' jobs, departments, and hospitals.

RESULTS

Departments most frequently reporting anesthetic gas use were operating rooms, post-anesthetic recovery rooms, and maternity units. In the cohort of 15,317 live-borne children of 9,433 mothers, 1,079 had congenital anomalies. Anomalies were associated with ever and probable maternal exposure to halogenated gases (ORs: 1.49, 95% CI: 1.04-2.13; and 2.61, 95% CI: 1.31-5.18, respectively) and to nitrous oxide (ORs: 1.42, 95% CI: 1.05-1.94; and 1.82, 95% CI: 1.11-2.99). Anomalies most frequently associated with exposure were those of the heart (OR, halogenated gases: 2.31, 95% CI: 1.07-4.97) and integument (OR, halogenated gases: 3.56, 95% CI: 1.53-8.32; OR, nitrous oxide: 3.02, 95% CI: 1.37-6.64). Gases most frequently associated with anomalies were halothane (predominantly used early in the study period), isoflurane, and sevoflurane (predominantly used later in the period).

CONCLUSIONS

In this study, where both exposures and outcomes were assessed objectively, certain congenital anomalies were associated with estimated anesthetic gas exposure.

Drug-induced arrhythmias

The objective of this review is to characterize the mechanisms, risk factors, and offending pharmacotherapeutic agents that may cause drug-induced arrhythmias in critically ill patients. PubMed, other databases, and citation review were used to identify relevant published literature. The authors independently selected studies based on relevance to the topic. Numerous drugs have the potential to cause drug-induced arrhythmias. Drugs commonly administered to critically ill patients are capable of precipitating arrhythmias and include antiarrhythmics, antianginals, antiemetics, gastrointestinal stimulants, antibacterials, narcotics, antipsychotics, inotropes, digoxin, anesthetic agents, bronchodilators, and drugs that cause electrolyte imbalances and bradyarrhythmias. Drug-induced arrhythmias are insidious but prevalent. Critically ill patients frequently experience drug-induced arrhythmias; however, enhanced appreciation for this adverse event has the potential to improve prevention, treatment, patient safety, and outcomes in this patient population.